Polysaccharides as Alternative Moisture Retention Agents for Shrimp.

Phosphates are used as moisture retention agents (MRAs) by the shrimp industry. Although they are effective, phosphates are expensive, need to be listed on a food label, and overuse can often lead to a higher product cost for consumers. Polysaccharides were researched as alternative MRAs. Polysaccharides are usually inexpensive, are considered natural, and can have nutritional benefits. Research was conducted to determine whether polysaccharides yielded similar functional impacts as phosphates. Treatments included a 0.5% fibercolloid solution isolated from citrus peel, an 8% pectin solution, a 0.5% xanthan gum (XG) solution, a 1% carboxymethyl cellulose solution, and conventionally used 4% sodium tripolyphosphate (STP). Experimental treatments were compared to a distilled water control to gauge effectiveness. Freezing, boiling, and oven drying studies were performed to determine how moisture retention in shrimp differed using these different treatments. Water activity was measured to determine any potential differences in shelf life. Solution uptake was also determined to understand how well the treatments enhanced water binding. For moisture loss by freezing, 4% STP and the 0.5% fibercolloid solution functioned the best. The 4% STP treated shrimp lost the least amount of moisture during boiling. The 0.5% fibercolloid and 0.5% XG treatment outperformed phosphates in respect to moisture uptake ability. None of the treatments had a major effect on water activity. All treatments were rated similar in consumer sensory acceptability tests except for pectin, which was rated lower by the sensory panel. Overall, polysaccharides were found to be viable alternatives to phosphates.

A region of mesial prefrontal cortex tracks monetarily rewarding outcomes: characterization with rapid event-related fMRI.

The function of the mesial prefrontal cortex (MPFC: including Brodman areas 10/12/32) remains an enigma. Current theories suggest a role in representing internal information, including emotional introspection, autonomic control, and a "default state" of semantic processing. Recent evidence also suggests that parts of this region may also play a role in processing reward outcomes. In this study, we investigated the possibility that a region of the MPFC would be preferentially recruited by monetary reward outcomes using a parametric monetary incentive delay (MID) task. Twelve healthy volunteers participated in functional magnetic resonance scans while playing the MID task. Group analyses indicated that while the ventral striatum was recruited by anticipation of monetary reward, a region of the MPFC instead responded to rewarding monetary outcomes. Specifically, volume-of-interest analyses indicated that when volunteers received $5.00 after anticipating a $5.00 win, MPFC activity increased, whereas when volunteers did not receive $5.00 after anticipating a $5.00 win, MPFC activity decreased, relative to outcomes with no incentive value. These findings suggest that in the context of processing monetary rewards, a region of the MPFC preferentially tracks rewarding outcomes.

Volition to action--an event-related fMRI study.

Current concepts of the anterior cingulate cortex (ACC) increasingly emphasize its role as an interface between limbic and neocortical functions. It has been pointed out that ACC activation reflects the intentional amount of effort (volition) that a subject uses in a task. In previous electrophysiological source localization investigations during a choice reaction task, we described a strong early activation in the ACC region approximately 120-150 ms after stimulus presentation. The degree of midline ACC activation correlated negatively with reaction time. This observation together with the finding that ACC activation precedes information processing in cortical association areas provided preliminary support to the notion that the extent of ACC activation is related to a subject's task engagement. However, due to the inverse problem and the relatively low spatial resolution of the electrophysiological measurements, we were not able to make inferences about the validity and the exact localization of the observed midline activation maximum. We addressed this question and performed an event-related fMRI study in six healthy volunteers during a visual choice reaction task. Two checkerboard stimuli were presented either in the left or right visual hemifield in randomized order and with an interstimulus interval requiring an appropriate motor response (left-right button press). A bilateral BOLD maximum was observed in the region of the supplementary motor area confluent with the neighboring motor area of the dorsal ACC. The degree of ACC activation correlated significantly with reaction time. These results are in line with our previous electrophysiological findings and provide further evidence that early ACC activation during a choice reaction task reflects the intentional effort of a subject to carry out a task.